Indexer sources can now be interrupted, and failed sources can have their

transactions rolled back.

src/contrib/cddadecoder/CddaIndexerSource.cpp

@@ -123,7 +123,7 @@ void CddaIndexerSource::OnAfterScan() {
     /* nothing to do... */
 }
 
-void CddaIndexerSource::Scan(musik::core::sdk::IIndexerWriter* indexer) {
+ScanResult CddaIndexerSource::Scan(IIndexerWriter* indexer) {
     for (auto disc : this->discs) {
         char driveLetter = disc->GetDriveLetter();
         std::string cddbId = disc->GetCddbId();
@@ -152,7 +152,11 @@ void CddaIndexerSource::Scan(musik::core::sdk::IIndexerWriter* indexer) {
         }
     }
 
-    discIds.clear();
+    return ScanCommit;
+}
+
+void CddaIndexerSource::Interrupt() {
+
 }
 
 void CddaIndexerSource::ScanTrack(

src/contrib/cddadecoder/CddaIndexerSource.h

@@ -52,13 +52,15 @@ class CddaIndexerSource :
         virtual void OnAfterScan();
         virtual int SourceId();
 
-        virtual void Scan(musik::core::sdk::IIndexerWriter* indexer);
+        virtual musik::core::sdk::ScanResult Scan(musik::core::sdk::IIndexerWriter* indexer);
 
         virtual void ScanTrack(
             musik::core::sdk::IIndexerWriter* indexer,
             musik::core::sdk::IRetainedTrackWriter* track,
             const char* externalId);
 
+        virtual void Interrupt();
+
         /* CddaDataModel::EventListener */
         virtual void OnAudioDiscInsertedOrRemoved();
 

src/core/library/Indexer.cpp

@@ -110,6 +110,10 @@ Indexer::~Indexer() {
         {
             boost::mutex::scoped_lock lock(this->stateMutex);
             this->exit = true;
+
+            if (this->currentSource) {
+                this->currentSource->Interrupt();
+            }
         }
 
         this->waitCondition.notify_all();
@@ -201,20 +205,40 @@ void Indexer::Synchronize(const SyncContext& context, boost::asio::io_service* i
 
     if (type == SyncType::All || (type == SyncType::Sources && sourceId == 0)) {
         for (auto it : this->sources) {
-            this->SyncSource(it.get());
-            this->trackTransaction->CommitAndRestart();
+            if (this->Exited()) {
+                break;
             }
+
+            this->currentSource = it;
+            if (this->SyncSource(it.get()) == ScanRollback) {
+                this->trackTransaction->Cancel();
+            }
+            this->trackTransaction->CommitAndRestart();
+
+            break;
+        }
+
+        this->currentSource.reset();
     }
 
     /* otherwise, we may have just been asked to index a single one... */
 
     else if (type == SyncType::Sources && sourceId != 0) {
         for (auto it : this->sources) {
+            if (this->Exited()) {
+                break;
+            }
+
             if (it->SourceId() == sourceId) {
-                this->SyncSource(it.get());
+                this->currentSource = it;
+                if (this->SyncSource(it.get()) == ScanRollback) {
+                    this->trackTransaction->Cancel();
+                }
                 this->trackTransaction->CommitAndRestart();
             }
         }
+
+        this->currentSource.reset();
     }
 
     /* process local files */
@@ -428,9 +452,9 @@ void Indexer::SyncDirectory(
     #undef WAIT_FOR_ACTIVE
 }
 
-void Indexer::SyncSource(IIndexerSource* source) {
+ScanResult Indexer::SyncSource(IIndexerSource* source) {
     if (source->SourceId() == 0) {
-        return;
+        return ScanRollback;
     }
 
     source->OnBeforeScan();
@@ -452,9 +476,11 @@ void Indexer::SyncSource(IIndexerSource* source) {
 
     /* now tell it to do a wide-open scan. it can use this opportunity to
     remove old tracks, or add new ones. */
-    source->Scan(this);
+    auto result = source->Scan(this);
 
     source->OnAfterScan();
+
+    return result;
 }
 
 void Indexer::ThreadLoop() {

src/core/library/Indexer.h

@@ -120,7 +120,7 @@ namespace musik { namespace core {
             void FinalizeSync(const SyncContext& context);
             void SyncDelete();
             void SyncCleanup();
-            void SyncSource(musik::core::sdk::IIndexerSource* source);
+            musik::core::sdk::ScanResult SyncSource(musik::core::sdk::IIndexerSource* source);
             void ProcessAddRemoveQueue();
             void SyncOptimize();
             void RunAnalyzers();
@@ -154,6 +154,7 @@ namespace musik { namespace core {
             std::shared_ptr<musik::core::Preferences> prefs;
             std::shared_ptr<musik::core::db::ScopedTransaction> trackTransaction;
             std::vector<std::string> paths;
+            std::shared_ptr<musik::core::sdk::IIndexerSource> currentSource;
             boost::interprocess::interprocess_semaphore readSemaphore;
     };
 

src/core/sdk/IIndexerSource.h

@@ -34,6 +34,7 @@
 
 #pragma once
 
+#include "constants.h"
 #include "IIndexerWriter.h"
 #include "ITrackWriter.h"
 
@@ -47,13 +48,15 @@ namespace musik { namespace core { namespace sdk {
 
             virtual void OnAfterScan() = 0;
 
-            virtual void Scan(IIndexerWriter* indexer) = 0;
+            virtual ScanResult Scan(IIndexerWriter* indexer) = 0;
 
             virtual void ScanTrack(
                 IIndexerWriter* indexer,
                 IRetainedTrackWriter* track,
                 const char* externalId) = 0;
 
+            virtual void Interrupt() = 0;
+
             virtual int SourceId() = 0;
     };
 

src/core/sdk/constants.h

@@ -87,6 +87,11 @@ namespace musik {
                 Prebuffer = 0x01
             };
 
+            enum ScanResult {
+                ScanCommit,
+                ScanRollback
+            };
+
             namespace category {
                 static const char* Album = "album";
                 static const char* Artist = "artist";